The Mechanisms app - Development of a new learning tool for active learning
in organic chemistry v13
COMPRESSED
Printed
2/28/2019
20
these moves begin to make sense and reveal where more guidance and
explanation is required. For example, reviewing data from Addition Puzzle 2,
hydration of 2-butene, exposed the belief that an oxygen with a positive charge
is an electrophile (Figure 7). This error was observed in both the first step,
addition of a proton to the alkene,
and in the last step, deprotonation. For an
expert, the hydronium is first-and-foremost a Brønsted-Lowry acid, so arrows
would move initially to the hydrogen atom. If, however, the acidity of
hydronium is not recognized, then this is actually a fairly logical step that
follows the commonly used saying “electron rich attacks electron poor.”
Figure 7: The accepted mechanism of Addition Puzzle 2 in the Mechanisms app.
Student attempts at using oxygen of hydronium as the electrophile shown below
the corresponding steps.
Addition Puzzle 2
also revealed that, students struggle with how to show proton
transfers in a mechanism. Multiple times students tried to have a proton leave
without the facilitation of a base (Figure 8a) or started the arrow from the
hydronium oxygen-hydrogen bond (Figure 8b). Perhaps students are trying to
complete the puzzle in the most efficient number of steps but then that means
they are do not fully understand why the flow of electrons follows the patterns it
does. Overall, data collected from Addition Puzzle 2
suggests students struggle
to recognize when to use the acid-base steps traditionally learned early on in
organic chemistry courses. Without a firm basis in this foundational chemistry
concept, more advanced mechanisms that include an acid-base, such as those
involving carbonyls, are going to be even more challenging for student. Ongoing
research carried out at two midwestern research intensive universities are
exploring these hypotheses with think-aloud studies of individual students using
the app
.
The Mechanisms app - Development of a new learning tool for active learning
in organic chemistry v13 COMPRESSED
Printed
2/28/2019
21
Figure 8: Common errors for deprotonation attempts a.) loss of a proton without
the assistance of a base and b.) movement of electrons from the hydronium
oxygen-hydrogen bond onto the base.
As more students continue to use the app
and play through the puzzles, it is
anticipated that more unexpected common errors will be recorded. Moving
forward, we plan to use this data to identify where students would benefit from
more hints and explanations. The inclusion of this automated guidance through
advanced analytics and machine learning will provide individualized feedback
for students and concept-based assessment for instructors, and is the ultimate
goal of the NSF SBIR research and development effort. As we continue to
improve the content and pedagogy of Mechanisms based
on user feedback, our
hope is that we can give all students the guidance they need to succeed in
organic chemistry.
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